Targeted therapies in ameloblastomas and amelobastic carcinoma-A systematic review.

Targeted therapy has the potential to be used in the neoadjuvant setting for odontogenic tumors, reducing the morbidities associated with major surgery. In this regard, the aim of this study was to summarize the current evidence on the different forms of targeted therapy, effectiveness, and drawbacks of this course of treatment. Four databases were searched electronically without regard to publication date or language. Grey literature searches and manual searches were also undertaken. Publications with sufficient clinical data on targeted therapy for odontogenic tumors were required to meet the criteria for eligibility. The analysis of the data was descriptive. A total of 15 papers comprising 17 cases (15 ameloblastomas and 2 ameloblastic carcinomas) were included. Numerous mutations were found, with BRAF V600E being most common. Dabrafenib was the most utilized drug in targeted therapy. Except for one case, the treatment reduced the size of the lesion (16/17 cases), showing promise. Most of the adverse events recorded were mild, such as skin issues, voice changes, abnormal hair texture, dry eyes, and systemic symptoms (e.g., fatigue, joint pain, and nausea). It is possible to reach the conclusion that targeted therapy for ameloblastoma and ameloblastic carcinoma may be a useful treatment strategy, based on the findings of the included studies.

Adenoid 'ameloblastoma': Clinicopathological description of 4 additional BRAF-negative cases.

OBJECTIVE: Adenoid ameloblastoma (AA) is an epithelial odontogenic tumor that was recognized as a separate entity in the last odontogenic classification of WHO in 2022. The etiology is unknown, and the pathogenesis remains controversial. The objective of this study is to contribute the clinicopathological features of 4 additional BRAF-negative cases to the existing literature, aiming to enhance the molecular understanding of this unique tumor in the forthcoming classification. MATERIALS AND METHODS: This study consists of a case series of four patients diagnosed with AA. The patients' demographic and clinical information were collected from the universities' medical achieves. Histopathologically, all cases were reexamined according to the latest update of the WHO odontogenic tumor classification. In addition to H&E and immunohistochemical stains, cytogenetics was also evaluated. RESULTS: Well-defined unilocular radiolucent lesions were observed in all cases. Ameloblastoma-like components exhibited reserved nuclear polarity, suprabasal stellate reticulum-like epithelium, duct-like structure, whorls/morules, and cribriform architecture were common features. Variable immunoreactivity to CK7, CK19, CK14, p63, and p40 were determined, and proliferative activity was greater than 15%. The BRAF molecular study revealed no mutations. CONCLUSIONS: When diagnosing AA, the essential histopathological characteristics must be rigorously applied, and a significant portion of the lesion should contain these features. Additionally, despite limited molecular data, since the BRAF mutation commonly observed in ameloblastomas is not present in the majority of AA cases, we propose changing the term "ameloblastoma" to "ameloblastic" and referring to it as "adenoid ameloblastic tumor" in the forthcoming classification.

The effect of glycine on oxidative stress, inflammation and renin-angiotensin system in kidneys and aorta of cyclosporine-administered rats.

Cyclosporine A (CsA) is an immunosuppressive drug, used in organ transplantations. Oxidative stress, inflammation and renin-angiotensin system (RAS) activation play an important role in CsA-toxicity. Glycine (Gly) has antioxidant and anti-inflammatory effects. In this study, Gly was investigated for its protective role against CsA-induced toxicity. CsA (20 mg/kg/day; subcutaneously) was administered to rats along with Gly injection (250 or 1000 mg/kg; intraperitoneally) for 21 days. Renal function markers [serum urea and creatinine and urinary protein and kidney injury molecule levels and creatinine clearance values] together with histopathological examinations were performed. Oxidative stress (reactive oxygen species, thiobarbutiric acid reactive substances, advanced oxidation products of protein, glutathione, ferric reducing anti-oxidant power and 4-hydroxynonenal levels), and inflammation (myeloperoxidase activity) were determined in kidney tissue. The RAS system [angiotensin II (Ang II) levels, and mRNA expressions of angiotensin converting enzyme (ACE), angiotensin II type-I receptor (AT1R)] and NADPH-oxidase 4 (NOX4) were measured in kidney and aorta. CsA caused significant disturbances in renal function markers, increases in oxidative stress and inflammation parameters and renal damage. Serum angiotensin II levels and mRNA expressions of ACE, AT1R and NOX4 elevated in the aorta and kidney of CsA-rats. Gly, especially its high-dose, alleviated renal function markers, oxidative stress, inflammation and renal damage in CsA-rats. Moreover, serum Ang II levels and mRNA expressions of ACE, AT1R and NOX4 decreased significantly in aorta and kidney in CsA-rats due to Gly treatment. Our results indicate that Gly may be useful for the prevention of CsA-induced renal and vascular toxicity.

Evaluation of Preventive Role of Systemically Applied Erythropoietin after Tooth Extraction in a Bisphosphonate-Induced MRONJ Model.

Background and Objectives: In this experimental study, the prophylactic effect of systemically administered erythropoietin (EPO) in medication-related osteonecrosis of the jaw (MRONJ) was evaluated. Materials and Methods: The osteonecrosis model was established using 36 Sprague Dawley rats. EPO was systemically applied before and/or after tooth extraction. Groups were formed based on the application time. All samples were evaluated histologically, histomorphometrically, and immunohistochemically. A statistically significant difference in new bone formation was observed between the groups (p < 0.001). Results: When new bone-formation rates were compared, no significant differences were observed between the control group and the EPO, ZA+PostEPO, and ZA+Pre-PostEPO groups (p = 1, 0.402, and 1, respectively); however, this rate was significantly lower in the ZA+PreEPO group (p = 0.021). No significant differences in new bone formation were observed between the ZA+PostEPO and ZA+PreEPO groups (p = 1); however, this rate was significantly higher in the ZA+Pre-PostEPO group (p = 0.009). The ZA+Pre-PostEPO group demonstrated significantly higher intensity level in VEGF protein expression than the other groups (p < 0.001). Conclusions: Administering EPO two weeks pre-extraction and continuing EPO treatment for three weeks post-extraction in ZA-treated rats optimized the inflammatory reaction, increased angiogenesis by inducing VEGF, and positively affected bone healing. Further studies are needed to determine the exact durations and doses.

Could Local Application of Hypoxia Inducible Factor 1-α Enhancer Deferoxamine Be Promising for Preventing of Medication-Related Osteonecrosis of the Jaw?

This experimental study investigates the prophylactic effect of deferoxamine (DFO) on medication-related osteonecrosis of the jaw (MRONJ). Thirty-six female Sprague Dawley rats received zoledronic acid (ZA) for eight weeks to create an osteonecrosis model. DFO was locally applied into the extraction sockets with gelatin sponge (GS) carriers to prevent MRONJ. The specimens were histopathologically and histomorphometrically evaluated. Hypoxia-inducible factor 1-alpha (HIF-1α) protein levels in the extraction sockets were quantified. New bone formation rate differed significantly between groups (p = 0.005). Newly formed bone ratios in the extraction sockets did not differ significantly between the control group and the GS (p = 1), GS/DFO (p = 0.749), ZA (p = 0.105), ZA-GS (p = 0.474), and ZA-GS/DFO (p = 1) groups. While newly formed bone rates were higher in the ZA-GS and ZA-GS/DFO groups than in the ZA group, the differences were not significant. HIF-1α levels differed significantly between groups (p < 0.001) and were significantly higher in the DFO and ZA-GS/DFO groups than in the control group (p = 0.001 and p = 0.004, respectively). While HIF-1α levels were higher in the ZA-GS/DFO group than in the ZA group, the difference was not significant. While HIF-1α protein levels and new bone formation rate were elevated in the DFO-treated group, the effect was not significant. Further large-scale studies are needed to understand DFO's preventative effects on MRONJ and the role of HIF-1α in MRONJ pathogenesis.

Distribution and Frequency of Salivary Gland Tumours: An International Multicenter Study.

BACKGROUND: Salivary gland tumours (SGT) are a relatively rare group of neoplasms with a wide range of histopathological appearance and clinical features. To date, most of the epidemiological studies on salivary gland tumours are limited for a variety of reason including being out of date, extrapolated from either a single centre or country studies, or investigating either major or minor glands only. METHODS: This study aimed to mitigate these shortcomings by analysing epidemiological data including demographic, anatomical location and histological diagnoses of SGT from multiple centres across the world. The analysed data included age, gender, location and histological diagnosis from fifteen centres covering the majority of the world health organisation (WHO) geographical regions between 2006 and 2019. RESULTS: A total of 5739 cases were analysed including 65% benign and 35% malignant tumours. A slight female predilection (54%) and peak incidence between the fourth and seventh decade for both benign and malignant tumours was observed. The majority (68%) of the SGT presented in major and 32% in the minor glands. The parotid gland was the most common location (70%) for benign and minor glands (47%) for malignant tumours. Pleomorphic adenoma (70%), and Warthin's tumour (17%), were the most common benign tumours whereas mucoepidermoid carcinoma (26%) and adenoid cystic carcinoma (17%) were the most frequent malignant tumours. CONCLUSIONS: This multicentre investigation presents the largest cohort study to date analysing salivary gland tumour data from tertiary centres scattered across the globe. These findings should serve as a baseline for future studies evaluating the epidemiological landscape of these tumours.

The World Health Organization Classification of Odontogenic Lesions: A Summary of the Changes of the 2022 (5th) Edition.

The 5th edition of the World Health Organization (WHO) Classification of Head and Neck Tumors opened to online access in March 2022. This edition is conceptually similar to the previous classification of odontogenic lesions. The only newly defined entity in odontogenic lesions is adenoid ameloblastoma, which is classified under benign epithelial odontogenic tumors. While not odontogenic, the surgical ciliated cyst is a new entry to the cyst classification of the jaws. In other respects, a very important change was made in the new blue books that added 'essential and desirable diagnostic criteria' for each entity to highlight the features considered indispensable for diagnosis. In this article, we review the odontogenic tumors and cysts of the jaw sections of the Odontogenic and Maxillofacial Bone Tumors Chapter, outlining changes from the 2017 WHO classification and summarizing the essential diagnostic criteria and new developments.

A Rare Case of Peripheral Compound Odontoma and Review of the Literature.

Peripheral or extraosseous odontogenic tumors are rare oral soft tissue enlargements which demonstrate the same histologic features of their intraosseous counterparts but emerge in gingiva and mucosa. In this paper we report a case of peripheral odontoma in a 12-years-old female patient presented asymptomatic swelling in the palatal site. After the clinical and radiographic examination, excisional biopsy was applied to the lesion located entirely in the soft tissue of maxillary incisors. Histopathologically presence of tooth-like structures containing dentin with regular canals and partly enamel matrix were observed. Our aim is to present the extremely rare case of peripheral odontoma and to review the literature for demonstrating the frequency and clinicopathologic features of this entity.

Evaluation of the Efficacy of Mineralized Dentin Graft in the Treatment of Intraosseous Defects: An Experimental In Vivo Study.

Background and Objectives: Dentin grafts have osteoinductive and osteoconductive properties and are considered as an alternative to autogenous graft. This study evaluates the efficacy of autogenous mineralized dentin graft (AMDG) alone or with xenograft and compares it with those of various graft materials used in the treatment of intraosseous bone defects. Materials and Methods: The third incisor teeth of six sheep (2-3 years old) were extracted and AMDG was obtained. Six defects were prepared on each tibia of these six sheep: empty defect (group E); autogenous graft (group A), dentin graft (group D), xenograft (group X), autogenous + xenograft (group A + X) and dentin + xenograft (group D + X). Three sheep in each group were sacrificed in the post-operative 3rd and 6th week and the histologic analyses were performed. Results: The D and D + X groups showed histological features similar to the other groups in the 3rd and 6th weeks. No statistically significant difference was found regarding the rates of new bone formation between the D and D + X groups (p = 1.0) and the other groups at both time intervals (p > 0.05). Conclusions: Similar results observed in this study between groups A, D, X, A + X and D + X demonstrate that AMDG can be successfully used in the treatment of intraosseous bone defects. Further experimental and clinical studies are needed to be able to evaluate the effectiveness of dentin grafts in different types of indications.

Radiological evaluation of the periosteal reactions in the jaws: a retrospective CBCT study.

OBJECTIVES: The objective of this study is to evaluate the relationship between the radiological features of periosteal reactions (PR) and histopathological features of the lesions. METHODS: A total of 4605 CBCT images were evaluated and they were classified according to their radiological differential diagnosis. Images with pathologies were listed according to their histopathological examinations as cystic lesions, benign tumours, malignant tumours, fibro-osseous lesions and osteonecrosis, while images without pathologies were listed as traumas and others. All groups were reclassified as with or without the presence of detected PR. RESULTS: Pathologies and traumas were detected in 1801 of 4605 patients. There were 3 PR in 1140 cystic lesions, 4 PR in 102 benign tumours, 16 PR in 43 malignant tumours, 67 PR in 156 osteonecrosis/osteomyelitis cases and 3 PR in 262 trauma cases. As a result of the chi-square test between groups, there was a significant relationship between histopathologic diagnoses and periosteal reaction patterns (p = 0.000). CONCLUSIONS: Although there is a significant overlap between the patterns of PRs, PRs can be used to narrow the possibilities in the differential diagnosis. However, PRs alone are not sufficient variables for differential diagnosis in the absence of cortical bone destruction, localization, clinical and systemic findings.

Conceptual changes in ameloblastoma: Suggested re-classification of a "veteran" tumor.

OBJECTIVES: The merging of ameloblastoma (AM) with mural unicystic ameloblastoma (UAM-M) was suggested by the 2017 WHO based on similar treatment needs. In an international multicenter study, we investigated the characteristics of their merged product (merged-AM) and raised the possibility of unifying AM and UAM (total-AM). MATERIALS AND METHODS: AM and UAM (luminal/intraluminal/mural), separate and combined, were analyzed for demographic/clinical/radiological features. ANOVA and chi-square tests were followed by univariate and multivariate analyses, and significance was set at p < .05. RESULTS: The patients' mean age was 39.6 ± 20.3 years in merged-AM (147 AM, 76 UAM-M), 45.1 ± 19.4 years in AM (p = .009). Merged-AM comprised 51.3% multilocular/48.7% unilocular tumors, AM comprised 72.5%/27.5%, respectively (p < .001). Merged-AM was associated with impacted teeth in 30.8%, AM in 18% (p = .023). The probability of merged-AM for multilocularity increased by 2.4% per year of age (95%CI 0.6-4.2, p = .009). Association with impacted teeth decreased by 7.9% per year of age (95%CI 1.9-14.39, p = .009). Merged-AM did not differ from total-AM (p > .05). CONCLUSIONS: Merged-AM partially differed from AM, but differences appeared to diminish in an age/time-wise manner. Merged-AM and total-AM were nearly indistinguishable. Therefore, AM and UAM may be considered a continuous spectrum of one type of tumor, further necessitating revision of the treatment approaches.

The importance of clinical and radiological findings for the definitive histopathologic diagnosis of benign fibro-osseous lesions of the jaws: Study of 276 cases.

PURPOSE: Benign fibro-osseous lesions (BFOLs) are heterogeneous intraosseous disease processes sharing overlapping histopathologic features and demonstrate a wide range of biological behavior. The aim of this study is to highlight the importance of clinical and radiological findings for the definitive histopathologic diagnosis of benign fibro-osseous lesions of the jaws. MATERIALS AND METHODS: This is a cross-sectional retrospective study evaluating the three main groups of BFOLs: Cemento-osseous dysplasia, ossifying fibromas, and fibrous dysplasia. Previously diagnosed BFOL cases were searched for thoroughly from the archives of Istanbul University, Institute of Oncology, Department of Tumor Pathology in between 2005 and 2015. Clinical and radiological data of these cases were identified and recorded. The histopathologic features were reevaluated from the H&E-stained slides. RESULTS: A total of 276 BFOL cases were identified and reevaluated for the study. The most common BFOL type was cemento-osseous dysplasia (n = 135), followed by cemento-ossifying fibroma (n = 77), fibrous dysplasia (n = 53) and juvenile ossifying fibroma (n = 11). The female/male ratio was 3.4:1 with a strong predilection for the 4th decade (n = 102). The mandible (n = 209) was the predominantly affected jaw. Prominent osteoblastic rimming around the bony lesion was commonly observed for cemento-ossifying fibroma (n = 60/77), followed by cemento-osseous dysplasia (n = 23/135). Predominant ossification patterns showed some differences among the groups. The most common radiological feature was the mixed radiolucent/radiopaque internal structure. CONCLUSION: Our results document various clinical, radiological and histopathologic findings of BFOLs. Even some histopathologic differences are observed, clinical and radiographic correlation is mandatory prior to the definitive histopathologic diagnosis of BFOLs for the prevention of possible misdiagnoses or inappropriate treatments.

Automated Detection and Classification of Oral Lesions Using Deep Learning to Detect Oral Potentially Malignant Disorders.

Oral cancer is the most common type of head and neck cancer worldwide, leading to approximately 177,757 deaths every year. When identified at early stages, oral cancers can achieve survival rates of up to 75-90%. However, the majority of the cases are diagnosed at an advanced stage mainly due to the lack of public awareness about oral cancer signs and the delays in referrals to oral cancer specialists. As early detection and treatment remain to be the most effective measures in improving oral cancer outcomes, the development of vision-based adjunctive technologies that can detect oral potentially malignant disorders (OPMDs), which carry a risk of cancer development, present significant opportunities for the oral cancer screening process. In this study, we explored the potential applications of computer vision techniques in the oral cancer domain within the scope of photographic images and investigated the prospects of an automated system for detecting OPMD. Exploiting the advancements in deep learning, a two-stage model was proposed to detect oral lesions with a detector network and classify the detected region into three categories (benign, OPMD, carcinoma) with a second-stage classifier network. Our preliminary results demonstrate the feasibility of deep learning-based approaches for the automated detection and classification of oral lesions in real time. The proposed model offers great potential as a low-cost and non-invasive tool that can support screening processes and improve detection of OPMD.

Ameloblastic Fibro-Odontoma: At the Crossroad Between "Developing Odontoma" and True Odontogenic Tumour.

Ameloblastic fibro-odontoma (AFO) is a controversial, rare benign mixed odontogenic tumour that was re-defined as "developing odontoma" in the 2017 WHO classification arguing that once dental hard tissues form, it is programmed to transform into odontoma. However, AFO still remains unclear in terms of its nature. We aimed to analyze a large series of AFOs and compare it to a large series of odontomas (ODs) in an attempt to set cut-off diagnostic parameters between these entities and discuss latest updates on AFO histopathologic, clinical and molecular features. A total of 23 well-documented AFOs were analyzed versus 310 ODs focusing on the age of the patients and size of the lesions. For AFO, mean age was 9.4 ± 3.9 years (range 3-16 years) and mean size (greatest diameter) was 2.9 ± 1.5 cm (range 0.8-5.5 cm). For OD-mean age was 26.5 ± 15.6 years (range 3-81 years), mean size 1.9 ± 0.9 cm (range 1-5 cm). Receiver operating curve (ROC) showed that a cut-off age of 13.5 years and below [area under the curve (AUC) 0.902, 95%CI 0.859-0.945; p < 001; sensitivity 80%, specificity 87%] and a cut-off size of 2.1 cm and above are likely to be associated with AFO (AUC 0.7, 95%CI 0.574-0.827; p = 0.001; sensitivity 57%, specificity 77%). Thus, the combination of age and lesion size may be used to distinguish between lesions of a true neoplastic nature (i.e., AFO) and hamartomatous formation (i.e., OD). Further molecular and genetic specifications are needed to provide a better understanding on the pathogenesis of AFO in support of our suggestion and aid in an accurate classification of AFO.

Observer agreement in the diagnosis of oral lichen planus using the proposed criteria of the American Academy of Oral and Maxillofacial Pathology.

BACKGROUND: Oral lichen planus (OLP) is a common chronic inflammatory condition with an undefined malignant transformation potential. There have been many attempts at providing a specific definition of OLP without conclusive outcomes. A new set of diagnostic criteria was proposed in 2016 by the American Academy of Oral and Maxillofacial Pathology (AAOMP) in an endeavour to resolve this issue, and this has not yet been evaluated. This study aimed to assess the utility of AAOMP proposed criteria for the diagnosis of OLP. METHODS: Five pathologists blindly assessed a cohort of 215 digital whole slide images (WSI) obtained from haematoxylin and eosin-stained microscopic slides. Forty-six WSI were included twice to assess the intra-observer agreement. Included cases were diagnosed clinically as either OLP or oral lichenoid reaction. Each pathologist was asked to utilize the AAOMP histopathological criteria while assessing slides. The variations in diagnoses were assessed by unweighted kappa statistics. RESULTS: The level of intra-observer agreement was very good (0.801 to 0.899). The level of inter-observer agreement among the observers varied from good (0.658) to very good (0.842) when the responses were categorized as evident/compatible OLP versus no OLP and was good (0.62 to 0.725) when the responses were categorized as evident OLP, versus compatible OLP, versus no OLP. The clinico-pathological correlation was 87.6%. CONCLUSION: A reliable level of agreement can be achieved by pathologists for the diagnosis of OLP using the AAOMP criteria for differentiation between lichenoid and other conditions. There are still limitations in discriminating OLP from oral lichenoid lesions microscopically.

Osteolipoma: a review of the literature and a rare case report.

OBJECTIVES: Lipomas are the most common benign mesenchymal tumors of soft tissue. According to previous studies, 1-4% of the cases has been observed in the oral cavity. A histological variant of lipoma featuring bone formation is called osteolipoma and has been very rarely observed (less than 1% of the total). In order to make a meaningful addition to this rare knowledge base, our study aims to provide a literature review and to report an additional case of osteolipoma. METHODS: An electronic search in the PubMed database with the keyword "osteolipoma" was conducted. Among 69 search results, only the cases of osteolipoma located in the "oral cavity" were included in this study. The findings of the previously reported 20 cases (in English) of osteolipoma of the oral cavity were organized in a table along with a new case of osteolipoma located in the mandibular buccal vestibule with radiological and histopathological findings provided by the authors. RESULTS: Osteolipoma affects both sexes and usually emerges in middle-aged or elderly patients with a long history of slow progression. Different imaging techniques may be utilized in the radiographic evaluation. CONCLUSION: Differential diagnosis includes a wide range of lesions; therefore, the clinical and radiographic evaluation should be confirmed by histopathological examination. The suggested treatment is complete surgical excision and follow-up, and the prognosis is generally good.

A review with an additional case: amelanotic malignant melanoma at mandibular gingiva.

The purpose of this review with an additional case is to evaluate the clinical, ultrasonographic and histopathological features of a rare case of Amelanotic Malignant Melanoma (AMM) at mandibular gingiva and to compare our case with other published AMMs at mandibular gingiva. A 52-year-old male patient with no systemic diseases was referred to our clinic with a soft tissue lesion at mandibular gingiva. Ultrasonographic examination was performed and a lesion with malignant features was observed. A periapical radiograph was taken to investigate bone destruction and biopsy was planned. Histopathological examination revealed AMM and a literature search was performed to congregate reports which were indexed in PubMed, ScienceDirect, and ResearchGate. Three AMM cases at mandibular gingiva were found. Doppler Ultrasound examination suggested bone destruction and a 1.8 cm × 0.6 cm soft tissue mass with well-defined borders and increased vascularity. Due to its hypervascularity, depth of invasion and destruction at the bone, the lesion was prediagnosed as a malignancy. Lack of melanin pigmentation caused the large immunohistochemical panel study. The tumour cells showed HMB45 and S100 positivity and they were negative with SMA, Desmin, CK1.3, and CK20. Routine ultrasound examination of all soft tissue lesions is very important for assessing features such as vascularity, bone destruction and depth of invasion to detect malignancy. Melanocytic-associated immunohistochemical markers are crucial for AMM diagnosis.

Evaluation of the presence of myofibroblasts and matrix metalloproteinase 1 expression in the stroma of oral verrucous hyperplasia and verrucous carcinoma.

BACKGROUND: Oral verrucous carcinoma is a low-grade subtype of oral squamous cell carcinoma that should be differentiated from oral verrucous hyperplasia, a premalignant lesion. Stromal activated myofibroblasts known as cancer-associated fibroblasts have an active role in the initiation and progression of the cancers via secretion of different molecules including matrix metalloproteinases. AIMS: This study is designed to understand the differences in the presence of myofibroblasts and expression of matrix metalloproteinase-1 in the adjacent stroma of verrucous carcinoma and oral verrucous hyperplasia (OVH). SETTINGS AND DESIGN: Cross-sectional study. MATERIAL AND METHODS: Twenty-seven OVH, 19 oral verrucous carcinoma (OVC), and 8 cutaneous verrucous carcinoma (CVC) specimens were analyzed for immunohistochemical (IHC) expression of α-smooth muscle actin (αSMA) and MMP-1. RESULTS: IHC studies for αSMA expression in nonvascular stromal cells of the adjacent stroma revealed mild or no expression in 81.4%, 73.7%, and 62.5% of the cases of OVH, OVC, and CVC groups, respectively. No significant difference was seen in αSMA expression index between OVH and OVC groups (Adj. Sig. = 0.220) and between OVC and CVC groups (Adj. Sig. = 1.00). Pairwise analysis revealed a significant difference in MMP-1 expression index between the groups. No significant correlation was observed between MMP-1 expression index and αSMA expression index in OVH (pv = 0.358) and OVC (pv = 0.388) groups. CONCLUSION: The differences in MMP-1 expression between OVH and OVC can be used as an adjunctive aid in challenging cases including disoriented or inadequate samples.

Effects of Platelet-Rich Fibrin on Hard Tissue Healing: A Histomorphometric Crossover Trial in Sheep.

Bone defects lead to aesthetic and functional losses, causing dental rehabilitation to be more difficult. The objective of this work is to histologically assess the hard tissue healing of bone defects filled with platelet-rich fibrin (PRF) alone or as an adjuvant for mixing with and covering anorganic bovine bone (ABB), compared to ABB covered with a resorbable collagen membrane (CM). This study was designed as a crossover animal study. Four 5-mm tibia defects, 5 mm apart from each other, were surgically created on the tibias of 6 sheep. The defects were randomly filled with ABB + CM; PRF alone; ABB+PRF; or were left empty. The animals were euthanized on days 10, 20, and 40 post-operatively. No group showed any signs of bone necrosis. Inflammation was observed in 2 control and 3 test defects with no statistically significant difference between groups at each time point. The ABB + CM and ABB + PRF groups experienced the highest bone regeneration ratios. No differences between the empty-defect and PRF groups were observed in regard to bone regeneration. No statistical difference was observed between the ABB+PRF and ABB + CM groups in regard to bone regeneration and the amount of residual graft material at each time point. The use of PRF should be preferred due to its autogenous origin, low cost, and ease of use.